Nonshockable cardiac arrest responsive to guideline-based CPR

Abstract

MedWire News: Individuals who experience out-of-hospital cardiac arrest (OHCA) from nonshockable rhythms are more likely to survive if they are given cardiopulmonary resuscitation (CPR) in line with updated guideline recommendations, a study shows.

Recent evidence has demonstrated that nearly 75% of cardiac arrests are due to nonshockable rhythms that do not respond to CPR. It was previously uncertain if these patients would benefit from the revised CPR approach that the American Heart Association developed in 2005 for use in patients with shockable cardiac arrest.

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"Now, for the first time, we have seen a treatment that improves survival specifically in these patients," said lead author of the study Peter Kudenchuk (University of Washington, Seattle, USA) in a press statement. "And that treatment is simply providing the more intense, quality CPR recommended in the new guidelines."

"You could save 2500 more lives each year in North America alone by implementing these changes."

The changes to the AHA's CPR guidelines in 2005 included reducing the number of initial back-to-back analyses and shocks, eliminating rhythm and pulse checks immediately after each shock, increasing the ratio of chest compressions to ventilation from 15:2 to 30:2, and doubling the required period of CPR between successive rhythm evaluations. This emphasis on chest compressions was reiterated in a 2010 guideline update.

In this study, Kudenchuk and team analyzed all 3960 patients with nontraumatic OHCA from nonshockable initial rhythms who were treated by prehospital providers in King Country, Washington, USA, over a 10-year period.

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They then compared 1-year survival rates between patients treated from 2000 through 2004 (control period, n=1774), before the guideline changed, and those treated from 2005 through 2010 (intervention period, n=2186), after the guideline changed.

Kudenchuk and team found that 1-year survival almost doubled from the control to the intervention period, from 2.7% to 4.9% (p=0.001).

Similarly, between the control and intervention periods, survival to hospital discharge improved from 4.6% to 6.8% (p=0.004) and neurologically favorable survival at discharge improved from 3.4% to 5.1% (p=0.005).

Multivariate adjustment showed that patients who experienced nonshockable OHCA between 2005 and 2010 were a significant 85% more likely to be alive 1 year on than those with the condition between 2000 and 2005.

"By any measure - such as the return of pulse and circulation or improved brain recovery - we found that implementing the new guidelines in these patients resulted in better outcomes from cardiac arrest," said Kudenchuk.

The authors conclude: "These findings lend further evidence that resuscitation protocols aimed at increasing the basic provision of CPR have the potential to improve outcomes for all victims of cardiac arrest."